METAGENOMIC ANALYSIS OF GUT MICROBIOME IN FRESHWATER PERCH Anabas testudineus

Anabas testudineus is an important aquaculture species in Southeast Asia (SEA). Like many other fish species, rapid development of aquaculture has led to disease outbreaks and a low survival rate in A. testudineus. Understanding the taxonomic diversity and uncovering potential probiotic stains residing in A. testudineus gastrointestinal (GI) microbiome is important in disease control and productivity in captivity.

In this study, metagenomics analyses using Illumina-sequencing showed that three bacterial phyla, Proteobacteria, Firmicutes and Fusobacteria were predominantly found in the gut microbiome of climbing perch, Anabas testudineus, from both farmed- and wild-type samples. The 16S rRNA gene sequence analyses revealed that opportunistic pathogens and beneficial bacteria were co-existed in the freshwater teleosts. Among the intestinal microbes, Proteobacteria, Klebsiella sp., Cronobacter sp., Salmonella sp., Proteus sp., Edwardsiella sp. and Morganella sp. were dominant in climbing perch's GI found in two different habitats. In contrast to most marine fishes, Vibrio is the dominant genus in the gut system. In general, farmed climbing perch hosted fewer microbial biodiversity and dominated primarily by Fusobacteria (F. nucleatum and F. mortiferum), while the wild climbing perch GI was largely harbored by Proteobacteria and Firmicutes.

Our study suggests the climbing perch GI microbiome may have influenced by geographical variations, or human factors in aquaculture. In terms of microbial similarity, the wild-type climbing perch has a more consistent bacterial diversity compared to those found on farms. Our work provides a comprehensive report on the microbial ecology in the intestines of adult wild- and farmed climbing perch. In short, the bacterial community structure is largely driven by their living environments.